Business Segments (Details 3) (USD $) In Millions, unless otherwise specified	7 Months Ended		12 Months Ended
	Dec. 31, 2013		Dec. 31, 2014		May 31, 2013		May 31, 2012
Revenue from External Customer [Line Items]
Net sales	$ 4,765.9		$ 9,055.8		$ 9,974.1		$ 11,107.8
Phosphate Crop Nutrients [Member]
Revenue from External Customer [Line Items]
Net sales	2,059.3		4,096.2		4,106.1		5,418.4
Potash Crop Nutrients [Member]
Revenue from External Customer [Line Items]
Net sales	1,312.3		2,828.8		3,434.5		3,174.4
Crop Nutrient Blends [Member]
Revenue from External Customer [Line Items]
Net sales	863.7		1,292.9		1,472.3		1,517.1
Other [Member]
Revenue from External Customer [Line Items]
Net sales	$ 530.6	[1]	$ 837.9	[1]	$ 961.2	[1]	$ 997.9	[1]

[1] Includes sales for animal feed ingredients and industrial potash.